"""A Pythagorean triplet is a set of three natural numbers, for which,
a^2+b^2=c^2
Given N, Check if there exists any Pythagorean triplet for which a+b+c=N
Find maximum possible value of product of a,b,c among all such Pythagorean triplets, If there is no such Pythagorean triplet print -1."""
# !/bin/python3

product = -1
d = 0
N = int(input())
for a in range(1, N // 3):
    """Solving the two equations a**2+b**2=c**2 and a+b+c=N eliminating c """
    b = (N * N - 2 * a * N) // (2 * N - 2 * a)
    c = N - a - b
    if c * c == (a * a + b * b):
        d = (a * b * c)
        if d >= product:
            product = d
print(product)
